


alien

by supernormal



Series: Alien Gen AU [1]
Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: ALIEN TENTACLE PUSSY, Alien Sex, Alien genitalia, Bondage, Confused Boners, Getting Together, M/M, Medical Bondage, Tenderness, Trans Male Asagiri Gen, Trans Male Character, Vaginal Sex, gynecology chair, has accompanying art, language barriers, more incredibly weird shit sorry!, more like scientific bondage LOL!, senku is an awkward horny virgin
Language: English
Status: Completed
Published: 2020-08-07
Updated: 2020-08-07
Packaged: 2021-03-05 20:15:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,369
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25761202
Author URL: https://archiveofourown.org/users/supernormal/pseuds/supernormal
Summary: Senku has Gen, an alien he’s been living with, strapped down to a chair in his basement, investigating his anatomy. One certain body part catches his attention and ends up driving him off track.(includes art)
Relationships: Asagiri Gen/Ishigami Senkuu
Series: Alien Gen AU [1]
Series URL: https://archiveofourown.org/series/1893076
Comments: 8
Kudos: 88





	alien

**Author's Note:**

> [here’s](https://64.media.tumblr.com/90e356ba628f34a514e969d5bb7f6ac8/0f709588adc21e16-e5/s2048x3072/d933d742ffd018244b8f5322d5c382866a3b4074.png) what gen looks like in this au (pic has explicit nudity), in the end note I drew a scene from the fic so stick around for that...
> 
> I have an au in my mind where gen is an alien and senku is a human who studies him and they fall in love (and fucc). Of course I'm writing porn for it because I'm a coomer 😂
> 
> in this they've been together (not together together) for a couple of months and Gen has a pretty rudimentary understanding of senkus language but there's still some barriers

Senku scribbled another note on his clipboard. _Yeah. He’s pretty much a human, just a purple one with antennae._

He scratched his head. Gen was strapped down and had been scouring every inch of his body for the past thirty minutes or so to study his anatomy: measuring, taking pictures and scribbling notes. All he found was that whatever Gen was, it was basically identical to a human. _That's convergent evolution for you._

To his surprise, Gen had agreed to be restrained to the repurposed gynecology chair and scrutinized by his scientist companion. He made no protests when Senku fastened the leather restraints over his wrists, legs, body, and neck. Not that Senku was complaining.

Of course, he didn't _need_ to strap him down, but some gut feeling deep inside him told him that it would make it easier. Or that's what he told himself was the case.

However, there was one part he hadn't looked at. Gen still had a pair of white panties on, one of the articles of clothing he bought for him after finding him crashed in his yard.

He squinted. _Should he?_ His data would be incomplete without it, after all. He wasn’t terribly interested in pussy, anyway. It would probably just look like any other human vagina.

He looked up at Gen. He was waiting patiently for whatever he was about to do, totally calm. It was Senku who was making a big deal out of this to himself.

_C’mon. Just a quick look. Nothing crazy._

He hovered his hands over the underwear, looking back up at Gen for confirmation. His eyes were wide but other than that he seemed okay. He sharply inhaled and pulled them down, and what he saw was nowhere near what he expected.

All over his labia majora were little tentacles—each couldn't be thicker than his pinky. The rounded tips glowed a soft blue.

Senku clapped his hand over his mouth. He’d never seen anything like this before. It took him a moment to process it: it was just so _bizarre._

But he couldn't stop looking. It was kind of mesmerizing. The tentacles subtly… pulsated? quivered? _Did that mean he was aroused?_

His train of thought was interrupted by Gen’s voice. _“Senku-chan?”_ He didn't have a huge vocabulary yet but his name was one of the things he could say. Senku was still learning to communicate with him.

He cleared his throat. “I… see… you have different parts here. Er, different from my kind,” he stammered.

“Oh! Different,” repeated Gen.

"Y-yeah." He loosened his tie. It was getting hot. Or maybe it was just him.

Gen probably knew something was up by now. Senku had been standing, staring down at him for an unnatural amount of time.

 _"Senku-chan?"_ he said again, as if trying to get his attention.

Senku forced a laugh. "Nothing's wrong, it's just…"

He cut himself short when he felt his underwear tighten. He knew he was getting hard. _Shit. Why right now._ Sweat beaded on his forehead. _Did Gen even know what an erection meant? Probably._

He glanced at the tent he was pitching and paused. The room was silent, save for their breathing. You could hear a pin drop. He looked back up at his companion. He noticed for the first time ever that Gen was… terribly attractive. His long eyelashes with those blue eyes. His hair, perfectly split down the middle black and white. His lavender skin with a glittery silver sheen. And his—

His breath hitched. Should he make a move? Gen was restrained. He couldn't run away. Would it be the right thing to do? His head was too cloudy to think rationally. Gen gazed up at him curiously, waiting. His pupils were blown. His chest delicately rose up and down with each breath. Senku clenched his teeth and felt his cock grow harder. The tendrils were softly glowing and starting to move, slowly waving like they were reaching for something to grasp, and a slimy secretion was coming out, making it gleam under the buzzing fluorescent light. His dick throbbed in his pants. He really had never seen anything like it. He saw that Gen’s face was flushed purple and that his breathing was quickening. His genitals were starting to visibly twitch and the feelers were engorged.

_It was as if it was made just for him._

He couldn't stop himself. He swore under his breath as he undid his belt as fast as he could, pulled the fly down, and whipped out his cock. He winced at how sensitive he was. Just touching it was too much already. His head was getting blurry; his only thought was _fuck him, fuck him, fuck him._

_“I…”_

He pressed the tip to his vulva, gasping softly at the texture. It was something entirely new and it was too good already and he had _barely started._ Gen bit his lip, his eyes fixed down on his cock. He bucked his hips forward as much as he could given the strap around his waist keeping him confined to the chair.

Senku furrowed his brow, unsure of how to communicate with him. _“Uhh… I want to…”_ he stuttered. He wasn't so confident that Gen would understand. But the way he looked at him made him think that he just might. _“Do you…”_ He trailed off. How would he ask?

He reached out to caress his cheek. Gen leaned into his touch. He wasn't nervous or off put by any means. Senku just didn't know how to move forward.

 _“Shit, Gen…”_ he was at a loss.

Down there, the villi constricted and throbbed against his cock. He didn't know if they moved reflexively in response to sexual arousal or if Gen could control them precisely like his own fingers. That's the kind of thing he was trying to find out, right? How did he get so off track?

He tilted his hips forward to push the tip more. It easily slid along the feelers thanks to the generous lubrication produced. He was so close to entering his hole; the head was right against it. He would be able to enter so easily. It was like Gen’s body was directly inviting him in.

He stroked his cheek again, fingers brushing over the jagged mark on his cheek. Gen had his eyes cast down, as if he was _waiting_ for Senku to get started. Senku’s heart was drumming in his chest.

_Should I…?_

He knew the answer already. He moved his hand down to grasp Gen’s hip and slowly, slowly, so slowly slid the tip in. It was silky smooth and so inviting. He couldn't hold back a pleasured groan, he felt like a huge load had been lifted off his shoulders already.

Gen let out an adorable little squeak and fidgeted around, but he looked as excited as Senku felt. His eyes were big as they watched Senku gingerly slide in the rest of his length.

“Are you… okay?” Senku whispered.

Gen nodded. He at least knew that a nod meant yes and that a head shake meant no.

Senku rubbed his hand up and down his body reassuringly. He was almost balls deep. Gen was taking his cock so well. Soon, Senku’s hips were flush with Gen’s ass. It was wet, slippery, and deliciously warm. He breathed heavily; his heart raced.

His tentacles were wiggling about, brushing against his groin and ticking his balls. The feeling was completely alien to him but the way they dragged against his skin, smearing his juices on him was really hot.

Senku tightened his grip on Gen’s love handles as a sort of signal that he was going to start moving. If verbal communication was going to be rocky then he’d rely on body language and gestures.

He tilted his hips back to pull away for the first time. He hissed at the intense pleasure; he was _so hard,_ hard in a way he had never been and eager to fuck in a way he had never been.

He slammed back in as fast as he came out. Gen whined and squirmed against the bondage.

 _”Fuck, if only you knew how good you felt.”_ He had never felt an excitement like this before. He moved like it was muscle memory and he had done this with him countless times, instinctively knowing just where to move to maximize their pleasure.

He built up to a steady pace of fucking him. In and out, in and out.The chair shook with each thrust, clattering on the bare concrete floor. Senku didn't let up. He was addicted already. The soft, slimy, warm texture drove him wild and he couldn't stop his hips.

 _“Ah—”_ He collapsed forward onto Gen, hips still moving. He embraced him tightly, wrapping his arms around him and burying his face into the crook of his shoulder. He didn't need to. Gen was already restrained. He couldn't get away. But he wanted to be closer. As close as he could.

_“I’m sorry our first time had to be like this,” _he whispered. He hoped he would understand. He wanted to tell him that next time it would be upstairs in his room on the sift bed and he would let him be on top and lead the way and he’d do anything in the works for him and— but not now. He'd tell him when they weren't in the middle of this. He cursed himself for not spending more time teaching him Japanese.__

__He heard the clattering of Gen’s wrists against the straps: he wanted out. Senku fumbled with the buckles, one after the other, struggling to multitask, and freed his wrists. Gen immediately hugged him back tightly._ _

__They embraced on the cold metal surface. Senku thrust in and out faster. It felt better than he ever could have dreamed of. Whenever he pulled out, the feelers dragged against his shaft, and when he plunged back in again they added extra lubrication. It was otherworldly. The fleshlight he had been using was nothing in comparison._ _

__Gen was panting hard and frantically bucking his hips up, trying to get him in deeper. He wasn't looking down to watch but had his eyes fixed right on Senku’s like he was the real thrill here. Senku gazed right back at him, unable to tear his eyes away either._ _

__And then he did something he never thought he’d do. He kissed Gen right on the mouth, not even concerned about whether or not kissing was a thing where he came from. First, it was just a press of the lips together. Gen let out a confused whine but didn't try to turn away. After a couple of moments building familiarity Senku coaxed Gen’s mouth open with his tongue and probed it inside his mouth, not stopping his hips for one second. Gen whimpered innocently but was accepting and even did his best to kiss him back._ _

__He pulled back, admiring the fucked-out expression on Gen’s face, Saliva smeared all over his mouth and chin. He did return to peck a few kisses around his mouth and neck while he pounded him._ _

__Senku felt himself near the edge. He wouldn't be able to last much longer. He collapsed on top of Gen once more to rest his muscles as he neared his finish._ _

__Gen raked his blunt fingernails across his back. _"S-Senku-chan,"_ he moaned right into his ear, trembling under him. It was at that point that Senku lost control and let loose deep inside of him. His hips stuttered and he growled with pleasure as he filled Gen's alien womb with his seed._ _

___"I’m gonna cum—fuuck—!"_ _ _

__Gen squealed when he felt the warm fluid flood inside of him. His legs pulled against the restraints, straining to lock themselves around Senku's waist. His muscles tensed up; he was climaxing as well. Senku felt the tentacles brushing against his balls and his vagina tighten as if they were coaxing the last drops of semen out of him. He groaned and held onto him firmly, drinking in every ounce of pleasure._ _

__When he had none left, he pulled out, leaving a lewd string of semen connecting the tip to his vulva. The villi were smeared with his cum all through the little peaks and crevices; he was a mess. Gen gasped for breath, his skin slick with sweat._ _

__Senku accidentally lost himself for a moment while gawking at the sight before snapping out of it. “R-Right.” He wiped him off with a cloth and then slid his panties back up._ _

__“I’ll get you out now.” He undid the restraints around his ankles and Gen closed his legs together instinctually._ _

___“Hah…_ Senku-chan… Feel good?” Gen smiled tiredly._ _

__“Aha, Y-Yeah,” Senku laughed nervously. “Hey, um… put this on.” He shrugged off his lab coat and draped it over Gen’s shoulders._ _

__He sweetly smiled and warmly hugged it over himself. “Thank you, Senku-chan!” Then he slid off the chair and onto his feet. His legs felt a little weak and shaky from the climax that just rocked him._ _

__”Oh… I’ll carry you.” He couldn't help but talk to him as if he were any other person. He just hoped he’d get the gist._ _

__He slid one arm under his thighs and one behind his back and scooped him up. Thankfully, he was light enough for someone like him to hold. He carried him princess-style up the stairs and to his room where he laid him down on his bed. He pulled the blankets over him._ _

__He sat on the side of the bed, gazing down at his partner, who had buried himself under the sheets._ _

__"So… was that alright? Or…"_ _

__A hand reached up and grabbed him by the collar._ _

___”Woah—”_ _ _

__Gen pulled him down next to him and nestled his head under his chin. Senku felt a low vibration under him and…_ _

___He can purr?_ _ _

__That's one thing he missed earlier. He pulled Gen close to him and pet his head, taking in the novel sensation of him purring. He still had a lot of thoughts racing through his head but one thing was for sure._ _

__He needed to go way harder with those Japanese lessons._ _

**Author's Note:**

> [here’s](https://64.media.tumblr.com/cc9add7b44b64cf5f41b12407a7e08ed/0f709588adc21e16-c0/s2048x3072/16beaf79e3569615aa80ff7d93b7f8f186a07229.png) a scene from the fic (obligatory warning for nsfw in the pic)
> 
> follow my [twitter](https://twitter.com/foggytrees) for more sengens I draw a lot of nsfw I want more followers there. Its on private so u have to request tho
> 
> there was this fuckin porn video of like a guy fucking an alien on an exam table and it gave me brainworms I actually thot it was sexy.


End file.
